Look lady (guessing from avatar), i totally want to respect your right to make an opinion ...
But there is little advice:
DONT ever tell anyone what their character is suppose to do, that is up to them ... allways.
And two more things:
his ambush often fails (perception/insight(?) check)) and he just looks pathetic.
Lucky you i gues ...
So far i have 858,2h played ... i dont count, but guess around 30 playthroughs at least ... and so far his ambush failed maybe twice, or thrice.

I believe its perception ... not many of my characters get high Wisdom.
Lae'zel does basically the same thing on the ship: threatens you with a huge weapon and says "Abomination, this is your end!" (cue tadpole).
She never get to any threatening ... between me and her blade was still several steppes of place, she was just cautious, while in the hells, shortly after we were tadpoled, shortly after dragon blow up tadpole pool just next to us, and just as i run into her ... i can understand her reaction.
Astarion attacked me ... litteraly, purposefully ... on sunny beach, between flowers and trees, with no enemy or hostile action threatening him anywhere nearby, and he lured me towards him to do exactly that.
Feel free to explain those situations however you want ofc.
But for me, there was huge difference.
An evil path can end with a full party, it just wasn't the way you chose to roleplay it.
Never said it cannot, did i? :P